Electrical conduits of the general type contemplated by the invention are flexible armored electrically grounded housing for containing insulated conductors. They are connected by suitable end fittings to electrical inlet or outlet boxes and the conductors are drawn through the conduits during installation. The most common form of conduit previously in use is a roll-formed metal channel having interlocking turns, with a cotton cord between the turns for dampening noise and copper wire wrapped about the channel to provide an electrical ground. The construction is heavy, rather expensive and of limited flexibility. The gaps between the turns of the channel are not welded and electrical conductivity during grounding is not always reliable. Rather complex threaded end fitting designs are necessary to insure connection with the end portions of such conduits.
Other electrical conduit designs are known consisting of plastic flexible tubes reinforced with wire or a plastic helix, but those are for use only in light service applications.
It is the principal object of the present invention to provide a heavy duty electrical conduit of composite or matrix construction which is an improvement over the armored conduit designs of the prior art described above.